Following Bel [1]} and Herrera et al. [2]}-[3]}, we develop formalism for structure scalars in \(f(R,T)\)  gravity
and introduce a couple of tensors, named \(Y_{\alpha \beta }\)  and \(X_{\alpha \beta }\) .
For this, we orthogonally decompose the Riemann curvature tensor and find that
\(X_{\alpha \beta }&=& \frac{1}{3f_R}\left[\mu +\Psi +\psi _{00}\right]h_{\alpha \beta }-\frac{1}{2f_R}\left[(1+f_T)\Pi +\psi _{11}-\psi _{22}\right]\left(\chi _\alpha \chi _\beta -\frac{1}{3}h_{\alpha \beta }\right)-E_{\alpha \beta },\\\nonumber Y_{\alpha \beta }&=& \frac{1}{6f_R}\left[\mu +3f_T\mu +(1+f_T)(3P_r-2\Pi )+\Psi +\psi _{00}+\psi _{11}+2\psi _{22}\right]h_{\alpha \beta }-\frac{1}{2f_R}\left[(1+f_T)\Pi \right.\\&&+\left.\psi _{11}-\psi _{22}\right]\left(\chi _\alpha \chi _\beta -\frac{1}{3}h_{\alpha \beta }\right)+E_{\alpha \beta }.\) 
